1. Field of the Invention
The present invention relates to component mounting apparatuses, and particularly to a subrack having plate members for mounting plug-in units therein.
2. Related Art
Subracks for receiving plug-in units therein have been known in the electronics industry for a long time. A typical subrack comprises two sidewalls each having four corners, and four module rails fixed between the sidewalls, the module rails conventionally being screwed to the corresponding corners of the sidewalls. Bottom, top and back walls are attached to the subrack, and cooperate with the sidewalls to define a receiving space therebetween and an open side. The plug-in units can be inserted into and removed from the receiving space via the open side. The plug-in units typically comprise mounting panels engaging with two front module rails to thereby hold the plug-in units in place. For a thorough understanding of this kind of subrack, refer to the IEEE (International Electrical and Electronics Engineers) Standard 1101.10 established in 1996.
To enable fastening of the mounting panels, the module rails are required to have rather elaborate structures. Typically, the module rails consist of extruded aluminum. P.R. China Pat. No. 99201828.5, U.S. Pat. No. 6,134,119 and U.S. Pat. No. 6,474,479 disclose a variety of such extruded aluminum module rails. The extruded aluminum module rails generally each comprise a transverse rail defining a plurality of longitudinal grooves therein, and a centering strip and a threaded strip received in respective of the grooves. A row of equidistant centering holes is defined longitudinally in the centering strip, and a row of equidistant threaded holes is defined longitudinally in the threaded strip corresponding to the centering holes. For production of these rather elaborate components, complicated tools are required. Manufacturing of the module rails is quite expensive. In addition, assembling the discrete components (i.e., the sidewalls, and the bottom, top and back walls) and the module rails to complete a subrack is unduly laborious.
Thus, a new subrack for plug-in units which overcomes the above-mentioned problems is desired.